<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>Document</title>
    </head>
    <body>
        <ul id="menu">
            <li class="menu-item">国内新闻</li>
            <li class="menu-item">国外新闻</li>
            <li class="menu-item">体育新闻</li>
            <li class="menu-item">娱乐新闻</li>
        </ul>


        <ul id="menu2">
            <li class="menu-item">国内新闻2</li>
            <li class="menu-item">国外新闻2</li>
            <li class="menu-item">体育新闻2</li>
            <li class="menu-item">娱乐新闻2</li>
        </ul>
    </body>

    <script>
        var menu1 = document.getElementById('menu');

        var lis =  menu1.getElementsByTagName('li');
        var items = menu1.getElementsByClassName('menu-item');

        console.log(menu1);

        console.log(lis);
        console.log(items);


        for (var i = 0; i < items.length; i++) {
            items[i].style.color =  '#ff0000';
        }
    </script>
</html>